Drier for granular and like materials



Feb. 1, 1938. E. FALKENSTEIN 1-: AL 2,106,869

DRIER FOR GRANULAR AND LIKE MATERIALS Filed May 21, 1937 a 5 l MT 10 16 \I a {i fjiau/(j. W

Patented Feb. 1, 1938 DRIER FOR PATENT OFFICE aromas GRANULAB m LIKE- m- TEBIALS Engelbert Falkenstcin,

Dusseldorf-Gerresheim,

and Emil Barthelmess, Dusseldorf-.Oberkmel.

Germany Application 8Claims.

driers for drying granequal or varying grain The invention relates to ular and like materials of size, wherein the material to be dried is fed into a drying chamber against the direction of flow of a hot gas current employed for drying. Driers working on this counter-current principle are well-known, but in prior machines a horizontal drying drum was employed and special devices had to be provided for the further conveyance of the material to be dried through the drum, or, to this end, the horizontal drum had to be provided with a conveying spiral and rotated. These arrangements involved a heavy consumption of energy for conveying the material and,

furthermore, eflicient drying was not obtained since the individual grains or particles of the material were not brought into intimate contact with the hot drying gas, owing to the manner in which the material was conveyed through the opposing gas current.

The principal objects of this invention are to simplify and cheapen the construction of driers working on the counter-current principle; to dispense with conveyor means, involving moving 2 parts, within the drying chamber for moving the material therein against the gas current; to increase the drying efllciency; to provide for the production of material of uniform grain size simultaneously with the drying; and to provide means performing dual functions, with resultant economy. 7

These objects are attained by means illustrated diagrammatically in the drawing forming part of this specification, in which Fig. 1 is an elevation illustrating a simple form of the drier;

Fig. 2 illustrates, Fig. 1 in combination means;

Fig. 3 is an elevation of a modification of thedrier of Fig. 2;

Fig. 4 is an elevation of a modified drying plant for producing flnely-gro d, dried, material; and

Fig. 5 illustrates, in elevation, afurther embod- 45 iment employing dual-functioning means.

Similar parts are referred to by the same reference numerals throughout. 7

The drier essentially comprises a substantially vertical drying chamber or shaft through which the hot gas currentfor drying passes downwards, while the material to be dried is injected upwards into the shaft so that the grains or particles of material travel upwards in the shaft under their own momentum against gravity. When their upward momentum is lost, the particles then fall in elevation, the drier .of with sifting and grinding May 21. 1937, Serial No. 144.034 Germany Jamal- 13, 1936 and are removed from the shaft at the. bottom. In this way, they are moved in the shaft without conveying means and are in a suspendedcondition while in contact with the drying gas, thereby ensuring rapid drying. Furthermore, 5 any coarser particles present travel a greater distance in the drying shaft owing to their larger mass and, thus, also a more uniform drying is obtained.

Referring to Fig. 1, moist material to be dried 10 is introduced into the hopper l and is thrown by a pneumatic injector 2 through the conduit 3 upwards into the vertical drying shaft I. The shaft illustrated consists of a plurality of superimposed rings 4', 4", 4", which are connected 15 together and built-up on a collecting funnel 5 and carry as upper closure 9. burner hood 6 carrying the burners I at the top. The heating gas is forced through the burners I at the top into the heating chamber 6, comes into contact here with the coarser and therefore m istest particles of the material and travels ownwards against the rising material and with the material falling back, being finally discharged, together with moisture taken up from the material, from the collecting funnel 5 through the outlet pipe 8 provided thereon into the flue 9. The dried material automatically falls into the col lecting funnel 5 and passes down into the discharge pipe "),from which it is delivered to a truck or other collector 12. The pipe I!) is fitted 30 with an escape valve H to regulate the delivery. This simple form of construction is intended for use with material of the same kind, the grain size of which is to be preserved, as, for instance, cereals, grass and the like. 35

Fig. 2 illustrates a drier as shown in Fig. .1, but combined witha sifting and grinding device, in order. toproduce from dissimilar material, siv multaneously with the drying, a final product of uniform grain size and low dust content. Below 40 the collecting funnel 5 is arranged a sloping sieve I3 and a.roller mill ll, with a conveyor worm l5 delivering from the mill to the injector 2. The coarser material which has not fallen through the meshes of the sieve l3 and which isstill moist to a certain extent slides into the roller mill I4, is comminuted there and returned by the worm IE to the injector 2. by which it is again injected into the shaft 4 and re-subje'cted to the drying process. i

In Fig. '3 a modification of the drier of Fig. '2 is illustrated. a The sifting. of the material falling out'of the drying shaft 4 is effected here by two adjustable guide-surfaces It and-i1, ina stead of by the sloping sieve l3 of Fig. 2. The guide-surfaces feed the mixture of .vapours and material to be dried more or less to the roller mill H or the separator IS. The latter separates the material and discharges it .to the collector I2, the vapours being discharged through the The embodiment illustrated in Fig. 4 is intended for use where a final product as fine as possible is to be obtained. The roller mill ll of Figs. 2 and 3 is replaced here by a fine-grinding roller mill l9, into which, after sifting by the guide-surfaces iii and II, the coarser material falls and is comminuted, after which it is again fed to the injector 2 by the conveyor worm IS. The already dry material passes, along with the vapours, through the horizontal conduit H to the separator i8 where the material is separated and discharged to the collector i2. The vapours pass from the separator i8 through the vertical conduit 20 to a flexible tube filter 2|, from which they are drawn into the open through an exhauster 22, while the entrained dust, which arises to a particularly great extent during the finegrinding, is collected by the filter and is discharged through an outlet 23.

Instead of the pneumatic injector, a mechanical device may be provided for injecting the material into the drying chamber. Fig. 5 illustrates a drier embodying a mechanical injector which also performs other functions in the drying process. The moist material introduced into the hopper i is injected by means of a centrifugal mill 24 through the conduit 3 into the vertical drying shaft 4, the coarser particles beingsimultaneously comminuted and the centrifugal mill acting as an exhauster, in order to produce the pressure required for the further conveyance of the dry material and the vapours. The material falling into the collecting funnel 5 is guided by adjustable guide-surfaces l6 and i1 arranged in the sloping conduit in, more or less according to grain size and moisture content, either again to the centrifugal mill 24 or to the separator la. The latter separates the dried material and discharges the vapours through the flue 9'. Of course, a dust collector as illustrated in Fig. 4 may also be embodied in this form of drier.

The rapid drying in the suspended condition according to the counter-current principle has the advantage that, by suitable choice of the diameter and the height of the drying chamber, the period of drying can be varied at will. The resistances in the drier are so small that in most cases an exhauster is 'not required, since the draught of the flue is sufilcient for discharging the vapours.

Although, for the purpose of more fully explaining the invention, some specific embodiments have been described and illustrated, it is to be clearly understood that the invention is not limited to the precise details described and shown, since many forms of the drier are possible, according to the purpose of use, and many modifications will be obvious to those skilled in the art without departing from the invention as defined in and by the appended claims.

We claim:

1. Method of drying granular and like material which comprises the step of injecting the material substantially vertically upwards into a counter-current of drying gas so that the material first travels upwards under its own momentum counter to the gas current and then falls, travelling with the gas current.

let for gas at the bottom of said shaft, and.

means below' said shaft for receiving treated material.

3. Drier for granular and like material, comprising a substantially vertical drying shaft,

means for passing drying gas downwards through said shaft, means for injecting material to be dried upwards into said shaft, a discharge outlet for gas at the bottom of said shaft, means below said shaft for dividing said material into coarse material and fine material, means for collecting and discharging said fine material, grinding means, means for conveying coarse material from said dividing means to said grinding means, and means for conveying ground material from said grinding means to said injecting means.

4. Drier for granular and like material, comprising a substantially vertical drying shaft, means for passing drying gas downwards through said shaft, means for injecting material to be dried upwards intosaid shaft, means below said shaft for dividing said material into coarse material and fine material, means for separating fine said separator, grinding means, means for conveying coarse material from said dividing means to said grinding means, and means for conveying ground material from said grinding means to said injecting means.

5. Drier for granular and like material, comprising a substantially vertical drying shaft, means for passing drying gas downwards through said shaft, means for injecting material to be dried upwards into said shaft, means below said shaft for dividing said material into coarse material and fine material, means for separating fine material from treating gas, a dust filter, a gas conduit connecting said separator and filter, a gas discharge outlet from said filter, grinding means, means for conveying coarse material from said dividing means to said grinding means, and meansfor conveying ground material from said grinding means to said injecting means.

6 Drier as defined in claim 2, in which the said injecting means is a pneumatic injector.

7. Drier for granular and like material, comprising a substantially vertical drying shaft, means for passing hot gas downwards through said shaft, said means including a hood mounted on the top of said shaft and heating means in said hood, means for indecting material to be dried upwards into said shaft, a discharge outlet for gas at the bottom of said shaft, and means below said shaft for receiving treated material.

8. Drier for granular and like material, comprising a substantially vertical drying shaft,

means for passing drying gas downwards through 

